1. Users. Once Facebook users learn that their public data will be used for these purposes, people will en masse make their profiles private. Not everyone will understand what is going on, but everyone with enough Facebook friends will figure out from their friends to make their profiles private.
2. The public. Public outrage is a powerful thing. Data-sharing on such an unprecedented scale would almost certainly trigger public outcry and/or boycott. People have an alternative to Facebook: G+. A boycott would not be such a big tragedy for people. Plus, you don't want your website to be known as the one that can get people fired.
3. Government. This is related to number 2. If enough people get mad, then Congress may pass laws to stop Narrative Data and similar companies from producing personal data mining products.